BACKGROUND: N-terminal brain natriuretic peptide (NT-proBNP) level is elevated in patients with acute and chronic heart failure. This study addresses whether NT-proBNP correlates with invasively measured hemodynamic parameters and whether a decrease of NT-proBNP over time correlates with invasively monitored hemodynamic improvement. METHODS AND RESULTS: Twenty consecutive patients with acute exacerbation of chronic heart failure (New York Heart Association class III-IV) were included in this prospective study. NT-proBNP and hemodynamic measurements by balloon-tipped pulmonary artery catheter were performed simultaneously. Recompensation strategies included vasodilators, diuretics, and inotropes. The patients were divided in 2 subgroups. Group A, by definition, had a hemodynamic improvement over 24 hours with an increase of cardiac index of >30% and a decrease of pulmonary capillary wedge pressure of >30%. Group B did not show a hemodynamic improvement. Group A had a decline of NT-proBNP levels to 42% of the baseline value over 32 hours. In group B, the NT-pro BNP levels did not change significantly over 32 hours. CONCLUSION: The decrease of NT-proBNP correlates with hemodynamic improvement in patients with decompensated heart failure. The relative changes of NT-proBNP seem to be a reliable diagnostic tool in monitoring these patients. There results have been confirmed in a larger patient group.